In order to solve the problem of coverage redundancy caused by uneven distribution of nodes in wireless sensor networks（ WSNs） distributed randomly

as well as existence of covering hole at the same time

an adaptive adjustment algorithm for WSNs coverage radius is proposed

which judging and analysis the sensor node density by setting the threshold. According to the degree of sensor nodes density monitoring area

node radius with coverage is adjusted in an adaptive way using the coefficient of node radius step. Set up wireless sensor node transmission power and emission radius model

and calculate the transmission power. Simulation show that the proposed algorithm can reduce overall power consumption of network increase network lifetime.